Surgical fastener applying apparatus

ABSTRACT

A fastener applying apparatus (20) includes an anvil half-section (100) and a cartridge receiving half-section (200) having a distal portion dimensioned to releasably receive a single use loading unit (“SULU”) (400) and a proximal portion configured to support a firing assembly (500). The firing assembly includes a stationary housing (502) and a firing lever (516) having one or more lever guide projections (522). The firing lever is slidable from a proximal end of the stationary housing to a distal end of the stationary housing to define a firing stroke. A clamping lever (300) is movable from an undamped position to a clamped position to releasably secure the distal anvil portion in close approximation with the SULU. The clamping lever defines one or more lever guide slots (316). The lever guide projection(s) is positioned to enter the lever guide slot(s) upon initiation of the firing stroke to inhibit movement of the clamping lever to the undamped position during the firing stroke.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage Application of PCT/US13/68247 under 35USC § 371 (a), the disclosure of the above-identified application is hereby incorporated by reference its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a surgical fastener applying apparatus and, more particularly, to a surgical fastener applying apparatus having reusable and disposable components.

2. Discussion of Related Art

Surgical fastener applying apparatus wherein tissue is first grasped or clamped between opposing jaw structures and then joined with surgical fasteners, are well known in the art. In some such apparatus, a knife is provided to cut the tissue which has been joined by the fasteners. The fasteners are typically in the form of surgical staples, although, other surgical fasteners may also be utilized, such as, for example, clips or two part polymeric surgical fasteners.

Surgical fastener applying apparatus typically include two elongated beam members which are used to capture or clamp tissue therebetween. Typically, one of the beam members carries a disposable cartridge assembly which houses a plurality of staples arranged in at least two lateral rows, while the other beam member includes an anvil which defines a surface for forming the staple legs as the staples are driven from the cartridge assembly. Where two part fasteners are used, the beam member which includes the anvil carries a mating part of the two part fastener, e.g. the receiver.

Generally, the staple formation process is affected by the interaction between one or more longitudinally moving camming members and a series of individual staple pushers. As the camming members travel longitudinally through the cartridge carrying beam member, the individual pusher members are biased upwardly into a backspan of the staples supported within the cartridge assembly to sequentially eject the staples from the cartridge. A knife may be provided to travel with the camming members between the staple rows to cut the tissue between the rows of formed staples. An example of such an instrument is disclosed in U.S. Pat. No. 7,631,794, which is incorporated herein in its entirety by reference.

SUMMARY

The present invention relates to a surgical fastener applying apparatus for applying surgical fasteners to tissue. In embodiments, the surgical fastener applying apparatus includes an anvil half-section including a distal anvil portion and a proximal handle portion, and a cartridge receiving half-section defining an elongated channel member. The elongated channel member has a distal portion dimensioned to releasably receive a single use loading unit and a proximal portion configured to support a firing assembly. The firing assembly includes a stationary housing and a firing lever having at least one lever guide projection extending from the firing lever. The firing lever is slidable from a proximal end of the stationary housing to a distal end of the stationary housing to define a firing stroke. A clamping lever is secured to the cartridge receiving half-section and includes a proximal handle portion. The clamping lever is operably associated with the anvil half-section and the cartridge receiving half-section and is movable from an unclamped position to a clamped position to releasably secure the distal anvil portion of the anvil half-section in close approximation with the single use loading unit. The proximal handle portion of the clamping lever defines at least one lever guide slot. The at least one lever guide projection is positioned to enter the at least one lever guide slot upon initiation of the firing stroke to inhibit movement of the clamping lever to the unclamped position during the firing stroke.

In embodiments, the clamping lever is releasably secured to the cartridge receiving half-section.

In embodiments, at least one of the proximal handle portion of the anvil half-section and the proximal handle portion of the clamping lever defines a plurality of apertures to facilitate cleaning and sterilization of the anvil half-section and/or the clamping lever.

In embodiments, the distal anvil portion of the anvil half-section defines a longitudinal slot extending therethrough. The longitudinal slot defines a relatively narrow bottom portion and a top portion that increasingly widens in a direction extending away from the bottom portion.

In embodiments, the firing assembly includes a stationary housing having a bottom surface and a protrusion extending downwardly from the bottom surface. The proximal portion of the elongated channel member of the cartridge receiving half-section defines an aperture configured to receive the protrusion of the stationary housing to releasably secure and align the firing assembly within the elongated channel member.

In embodiments, the firing assembly is configured to be releasably secured within the cartridge receiving half-section prior to releasably securing the single use loading unit within the elongated channel member.

In embodiments, a biasing member is supported in a distal end of the firing assembly. The biasing member is configured to inhibit full seating of the single use loading within the elongated channel member prior to movement of the clamping lever to the clamped position.

In embodiments, the anvil half-section includes a proximally located bar and the cartridge receiving half-section includes a pair of proximally located support members that each define a vertical slot. The bar is configured to be received within the vertical slots to pivotably support the anvil half-section in relation to the cartridge receiving half-section.

In embodiments, the clamping lever includes a pair of inwardly-extending projections and the cartridge receiving half-section defines a pair of dimples. The projections of the clamping lever are configured to be received within the dimples of the cartridge receiving half-section to releasably retain the clamping lever in an intermediate position between the clamped position and the unclamped position.

In embodiments, the at least one lever guide slot has a mouth. The at least one lever guide projection is positioned to enter the mouth of the at least one lever guide slot upon movement of the clamping lever to the clamped position.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the presently disclosed surgical fastener applying apparatus will now be described herein with reference to the accompanying figures wherein:

FIG. 1 is a side perspective view of an embodiment of the presently disclosed surgical fastener applying apparatus in the clamped position;

FIG. 2 is a side perspective view of the surgical fastener applying apparatus of FIG. 1 during assembly of the clamping lever and the cartridge receiving half-section;

FIG. 3 is a side perspective view of the surgical fastener applying apparatus of FIG. 1 shown with parts separated;

FIG. 4A is a side perspective view of the anvil half-section of the surgical fastener applying apparatus of FIG. 1;

FIG. 4B is a bottom perspective view of the anvil half-section of FIG. 4A;

FIG. 5 is a bottom, perspective view of the proximal end portion of the anvil half-section of FIG. 4A;

FIG. 6A is a side view of the proximal end of the anvil half-section and cartridge-receiving half-section of the surgical fastener applying apparatus of FIG. 1 shown disengaged from one another;

FIG. 6B is a side view of the proximal end of the anvil half-section and cartridge-receiving half-section of FIG. 6A shown engaged to one another;

FIG. 7A is a bottom perspective view of the cartridge-receiving half-section of the surgical fastener applying apparatus of FIG. 1;

FIG. 7B is a side view of the cartridge-receiving half-section of FIG. 7A;

FIG. 8 is an enlarged side perspective view of the area of detail indicated in FIG. 7A;

FIG. 9 is a side perspective view of the firing assembly of the surgical fastener applying apparatus of FIG. 1;

FIG. 10 is bottom perspective view of the proximal end of the stationary housing of the firing assembly of FIG. 9;

FIG. 11A is a longitudinal cross-sectional view of the cartridge receiving half-section of the surgical fastener applying apparatus of FIG. 1 with the single use loading unit (“SULU”) partially engaged therein;

FIG. 11B is a longitudinal cross-sectional view of the cartridge receiving half-section of FIG. 11A with the SULU fully engaged therein;

FIG. 12A is a bottom perspective view of the distal portion of the anvil half-section of the surgical fastener applying apparatus of FIG. 1;

FIG. 12B is a top perspective view of the distal portion of the anvil half-section of FIG. 12A;

FIG. 13 is a transverse cross-sectional view taken across section line 13-13 of FIG. 12B;

FIG. 14A is a top perspective view of the clamping lever of the surgical fastener applying apparatus of FIG. 1; and

FIG. 14B is a side view of the clamping lever of FIG. 14A.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the presently disclosed surgical fastener applying apparatus will now be described in detail with reference to the drawings wherein like reference numerals identify similar or identical structural elements in each of the several views. As used herein, as is traditional, the term “proximal” refers to the end of the apparatus which is closer to the user, while the term distal refers to the end of the apparatus which is further away from the user.

FIGS. 1-2 illustrate an embodiment of the presently disclosed surgical fastener applying apparatus shown generally as surgical stapler 10. Surgical stapler 10 includes an anvil half-section 100, a cartridge receiving half-section 200, a clamping lever 300, a single use loading unit 400 (hereinafter “SULU”), and a firing assembly 500. Anvil half-section 100, cartridge receiving half-section 200, and clamping lever 300 may be configured as reusable components and, as such, may be constructed from biocompatible materials suitable for sterilization and repeated use, e.g., stainless steel. As will be described below, anvil half-section 100, cartridge receiving half-section 200 and clamping lever 300 each include features to facilitate effective sterilization thereof. SULU 400 and firing assembly 500, on the other hand, are disposable components and are separable from the reusable components of surgical stapler 10. SULU 400 and firing assembly 500 may be constructed from any suitable biocompatible material including plastics, metals, or combinations thereof. Further, surgical stapler 10 may be configured to receive or accommodate SULUs and/or firing assemblies for firing staples of different staple line lengths, e.g., 60 mm, 80 mm, and 100 mm.

Referring to FIGS. 4A-4B and 12A-13, anvil half-section 100 includes a proximal handle portion 102 and a distal anvil portion 104. Distal anvil portion 104 includes a staple deforming portion 106 (FIG. 4B) which includes a plurality of staple deforming recesses 108 (FIG. 12B) defined within bottom surface 110 thereof. Staple deforming portion 106 can be formed integrally with anvil half-section 100, or in the alternative, secured to anvil half-section 100 by a fastening process such as welding, tacking, or crimping, or other adhesive. Bottom surface 110 of distal anvil portion 104, which defines staple deforming portion 106, is configured to face a top surface of SULU 400 (FIG. 3) when SULU 400 (FIG. 3) is positioned in channel member 202 of cartridge receiving half-section 200 (see FIG. 2). Distal anvil portion 104 defines a central longitudinal slot 112 (FIGS. 12A-13) which extends along a substantial portion of the length of anvil portion 104. As best shown in FIGS. 12A-13, central longitudinal slot 112 has a relatively-narrow bottom portion 114 that extends through bottom surface 110 of staple deforming portion 106 for slidably receiving knife 406 of SULU 400 (see FIG. 3) as knife 406 is moved through SULU 400 (see FIG. 3) to cut tissue between the lateral rows 115 of staples (FIG. 12B). As shown in FIG. 13, top portion 116 of central longitudinal slot 112 gradually widens from bottom portion 114 to top surface 118 of distal anvil portion 104, wherein central longitudinal slot 112 defines a relatively wide opening. By providing a central longitudinal slot 112 that widens as shown, less material is required to form the distal anvil portion 104, thereby reducing the weight of the distal anvil portion 104. In addition, the widened slot 112 allows for more effective cleaning and sterilization of the distal anvil portion 104.

With reference to FIGS. 1-5, and to FIGS. 4A-4B in particular, a central portion 120 of anvil half-section 100 is defined between the proximal end of staple deforming portion 106 of distal anvil portion 104 and the distal end of proximal handle portion 102 of anvil half-section 100. Central portion 120 of anvil half-section 100 includes two pairs of cylindrical lateral support members 124, 126. Central portion 120 of anvil half-section further includes at least one protrusion such as a pair of support fingers 125 extending downwardly towards cartridge receiving half-section 200. During assembly of anvil half-section 100 and cartridge receiving half-section 200, lateral support members 124 function to set the minimum gap between SULU 400 (FIG. 3) and staple deforming portion 106 of anvil half-section 100 when surgical stapler 10 (FIG. 1) is in the clamped position. Lateral support members 126, on the other hand, are supported in U-shaped recesses 212 defined in central portion 210 of cartridge receiving half-section 200 (see FIGS. 7A-7B) to properly align SULU 400 (FIG. 3) relative to staple deforming portion 106 of anvil half-section 100 when surgical stapler 10 (FIG. 1) is in the clamped position. Further, in the clamped position, lateral support members 126 are received in cutouts 310 formed on spaced flange portions 308 of clamping lever 300. As stapler 10 is moved to the clamped position, support fingers 125 urge SULU 400 (FIG. 3) fully into position within channel member 202 of cartridge receiving half-section 200.

With continued reference to FIGS. 4A-4B in particular, proximal handle portion 102 of anvil half-section 100 is ergonomically formed and includes a body portion 128 and a thumb-engaging abutment 130. Body portion 128 may define a plurality of apertures 132 that facilitate the cleaning and sterilization of proximal handle portion 102. The provision of apertures 132 in body portion 128 also reduces the overall weight of surgical stapler 10.

With additional reference to FIG. 5, a proximal end of proximal handle portion 102 includes a downwardly extending protrusion, finger 134 which defines a rear locator bar 136 which will be discussed in further detail below (FIGS. 6A-6B). Rear locator bar 136 may assume a variety of configurations, e.g., cylindrical, tear-drop shaped, etc. Rear locator bar 136 may include at least one projection extending laterally therefrom. As best shown in FIG. 5, bar 136 may be integrated with, e.g., monolithically formed with, proximal handle portion 102 of anvil half-section 100 towards the proximal end thereof.

Referring to FIGS. 7A-8, cartridge receiving half-section 200 defines an elongated channel member 202 which defines a substantially U-shaped channel 204 having a distal portion 206 dimensioned to releasably receive SULU 400 (FIG. 3) and a proximal portion 208 dimensioned to releasably receive firing assembly 500 (FIG. 9). Cartridge receiving half-section 200 further includes a central portion 210 defining spaced U-shaped recesses 212 which are positioned to support lateral support members 126 of anvil half-section 100 (see FIGS. 1-3), as mentioned above. Central portion 210 of cartridge receiving half-section 200 further includes a pair of downwardly extending fingers 214 positioned beneath recesses 212. Fingers 214 each support a cylindrical pivot member 216 which is configured to be received within a respective C-shaped recesses 314 of a spaced flange portion 308 of clamping lever 300 to facilitate clamping of surgical stapler 10 (see FIGS. 1-3), as will be described below. Each one of a pair of dimples 218 defined within central portion 210 of cartridge receiving half-section 200 is configured to receive a projection 312 of clamping lever 300 to releasably secure clamping lever 300 (see FIGS. 1-3) in an intermediate position, between the clamped and unclamped positions, as will be described below.

With additional reference to FIGS. 1-3, base surface 220 of proximal portion 208 of elongated channel member 202 defines an elongate longitudinal slot 222 that is configured to permit passage of biasing member 506 (FIG. 3), e.g., a flat spring, of firing assembly 500, as will be described below, to bias clamping lever 300 towards the unclamped position. Positioning biasing member 506 (FIG. 3) on the disposable firing assembly 500, rather than on the reusable cartridge receiving half-section 200 or clamping lever 300 obviates the need to sterilize in and around the biasing member 506 (FIG. 3) after use. In other words, neither cartridge receiving half-section 200 nor clamping lever 300 need include complex features configured to retain biasing member 506 (FIG. 3) therein and, thus, are easily sterilized. Base surface 220 of elongated channel member 202 further defines a proximally located aperture 224 that is configured to receive a protrusion 504 (FIG. 10) which extends outwardly from a bottom surface of stationary housing 502 of firing assembly 500 to secure and align firing assembly 500 within elongated channel member 202, as will be described below.

With reference to FIGS. 6A-6B, the proximal end of cartridge receiving half-section 200 includes a pair of vertical support members 226. Each vertical support member 226 defines an elongated vertical slot 228 which may have a rounded bottom surface, although other configurations are contemplated. Vertical slots 228 are each dimensioned to receive rear locator bar 136 of finger 134, which is integral with and extends from the proximal end of anvil half-section 100, as mentioned above. During assembly, rear locator bar 136 is inserted into each of the vertical slots 228 to pivotably support anvil half-section 100 on cartridge receiving half-section 200 and axially locate cartridge receiving half-section 200 in relation to anvil half-section 100. With positioning bar 136 supported within vertical slots 228 of support member 226, anvil half-section 100 can be pivoted in a scissor-like manner with respect to the cartridge receiving half-section 200 between open and closed positions.

Referring to FIGS. 1-3 and 7A-10, firing assembly 500 includes stationary housing 502 having a proximal end including a protrusion 504 (FIG. 10). As discussed above, the protrusion 504 extends from the bottom surface of the stationary housing 502 and is configured for receipt within aperture 224 defined within base surface 220 of elongated channel member 202 to releasably secure and align the proximal end of firing assembly 500 within proximal portion 208 of elongated channel member 202. Likewise, SULU 400 (FIG. 3) includes a pair of distal protrusions 414 (FIG. 3) which are positionable within cutouts 230 formed at the distal end of channel member 202 to releasably secure the distal end of SULU 400 within the distal portion 206 of channel member 202. As will be described in further detail below with reference to FIGS. 11A-11B, stationary housing 502 of firing assembly 500 includes a biasing member 526 which is positioned to inhibit the proximal end of SULU 400 from fully seating within channel member 202 during assembly, thereby serving as a lockout to inhibit accidental firing of firing assembly 500. The proximal end of SULU 400 is only moved into proper operational position within channel member 202 upon clamping of stapler 10, wherein sufficient force is provided on SULU 400 to fully seat SULU 400 within channel member 202 against the bias of biasing member 526, as will be discussed in further detail below.

Referring to FIG. 9, stationary housing 502 of firing assembly 500 is configured to house the working components of firing assembly 500. For purposes herein, it suffices to say that stationary housing 502 generally supports a knife actuating bar 508, a cam bar 510, a guide block 512, a slide block 514, a firing lever 516, as well as other inter-cooperating components (not explicitly shown) that function to sequentially fire a plurality of surgical fasteners from SULU 400 (FIG. 3) and to advance knife 406 (FIG. 3) through SULU 400 (FIG. 3) to subsequently divide tissue between the lateral rows 115 (FIG. 12B) of staples upon actuation of firing lever 516. A more detailed description of a firing assembly similar to firing assembly 500 can be found in U.S. Pat. No. 7,631,794 (“the '794 Patent”), which is incorporated herein by reference in its entirety.

Firing lever 516 of firing assembly 500 includes first and second finger engagement members 518 and 520, either one of which can be selectively engaged to move the firing lever 516 through a firing stroke from either side of stapler 10. Firing assembly 500 is configured such that firing lever 516 must first be pivoted to one side or the other of firing assembly 500 before firing lever 516 can be moved through a firing stroke. A lever guide projection 522 extends from a bottom surface of each engagement member 518, 520. With additional reference to FIGS. 1-3 and 14A-14B, each lever guide projection 522 is configured and dimensioned for receipt within a respective lever guide slot 316 defined on each side of clamping lever 300 upon actuation of firing lever 516, i.e., upon initiation of the firing stroke. As will be described below, the appropriate lever guide slot 316 of clamping lever 300 receives the corresponding lever guide projection 522 of firing lever 516 (depending on which side firing lever 516 is pivoted to prior to firing) to both guide translation of firing lever 516 and to inhibit unclamping of clamping lever 300 once the firing stroke has been initiated, i.e., once firing lever 516 has been moved distally from a fully retracted position. As used herein, a firing stroke is defined as movement of firing lever 516 from the fully retracted position to a fully advanced position, while initiation of the firing stroke is defined as the movement of firing lever 516 sufficiently so as to position one of the lever guide projections 522 within the respective lever guide slot 316.

Referring again to FIGS. 1-3, SULU 400 includes a body 402 housing a plurality of staple pushers (not shown), a bottom cover 404, a knife 406 having an angled sharpened leading edge or blade (not shown), a plurality of staples (not shown) operably disposed within body 402, and a pivotally mounted safety lockout 408 (FIGS. 11A-11B), which is described in greater detail in the '794 Patent, previously incorporated herein by reference. Body 402 has a plurality of rows of staple retaining slots 410, e.g., four, six, etc. and a linear slotted knife track 412 centrally disposed in body 402. Surgical stapler 10 can be dimensioned to receive or accommodate SULU's of different staple line lengths including, e.g., 60 mm, 80 mm and 100 mm. Knife 406 may include a downturned hook portion (not shown) which is configured to engage upturned hook portion 524 (FIG. 11A) of knife actuating bar 508 of firing assembly 500, as also described in the '794 Patent. With reference in particular to FIGS. 11A-11B, as mentioned above, a biasing member 526 is supported in a distal end of stationary housing 502 of firing assembly 500 (FIG. 9). Biasing member 526 is positioned and configured to inhibit the proximal end of SULU 400 from fully seating within channel member 202 during assembly to inhibit accidental firing of firing assembly 500. More specifically, biasing member 526 prevents SULU 400 from fully seating in channel member 202 until stapler 10 is moved to a clamped position to prevent the firing assembly 500 (FIG. 9) from operably engaging SULU 400. The proximal end of SULU 400 is only moved into the fully seated position within channel member 202 upon clamping of stapler 10, at which time the downturned hook portion (not shown) of knife 406 is operably positioned for engagement with upturned hook portion 524 (FIG. 11A) of knife actuating bar 508 (FIG. 9). During a firing stroke, cam bar 510 (FIG. 9) is slidably movable through body 402 to eject staples from SULU 400. Concurrently, but after a preset delay, knife 406 is advanced through SULU 400 via advancement of knife actuating bar 508 (FIG. 9) to divide tissue between the lateral rows 115 of staples. A more detailed description of a SULU similar to SULU 400 can be found in the '794 Patent.

Referring now to FIGS. 14A-14B, in conjunction with FIGS. 1-3, clamping lever 300 includes a handle portion 302 including a grip 304 and a thumb engaging abutment 306. As mentioned above, a pair of spaced flange portions 308 are supported on the distal end of clamping lever 300. Each flange portion 308 defines a cutout 310 dimensioned to receive a respective lateral support member 126 of anvil half-section 100 to facilitate movement of surgical stapler 10 from an unclamped position to the clamped position (FIG. 1). Flange portions 308 each further include an inwardly-extending projection 312 configured to be received within dimples 218 defined within central portion 210 of cartridge receiving half-section 200 in snap-fit fashion upon pivoting of clamping lever 300 towards the clamped position to releasably secure clamping lever 300 in an intermediate position between the clamped and unclamped positions.

As discussed above, each flange portion 308 also defines a C-shaped recess 314 that is configured to receive cylindrical pivot member 216 of cartridge receiving half-section 200 to permit pivoting of clamping lever 300 relative to cartridge receiving half-section 200 between the unclamped and clamped positions. Clamping lever 300 is fully removable or separable from cartridge receiving half-section 200 by removing flange portions 308 of clamping lever 300 from about cylindrical pivot members 216 of cartridge receiving half-section 200. This configuration allows for greater access to both clamping lever 300 and cartridge receiving half-section 200 and eliminates difficult-to-reach areas of both components, thereby facilitating the cleaning and sterilization of both components.

With continued reference to FIGS. 14A-14B, handle portion 302 of clamping lever 300, as also discussed above, includes a longitudinal lever guide slot 316 which extends along each side thereof. Lever guide slots 316 each define an opening, or mouth 318 configured to receive the lever guide projection 312 of a corresponding finger engagement member 518, 520. More specifically, upon initiation of the firing stroke, the lever guide projection 522 moves from within mouth 518 into the corresponding lever guide slot 316. When the lever guide projection 522 is disposed within the lever guide slot 316, unclamping of clamping lever 300 is inhibited.

Handle portion 302 of clamping lever 300 further defines a plurality of apertures 320 that facilitate cleaning and sterilization of clamping lever 300 and reduce the overall weight of surgical stapler 10. Biasing member 506 (FIG. 3), which extends downwardly from firing assembly 500 through slot 222 (FIG. 7A) defined within cartridge receiving half-section 200, is configured to engage the inner surface of clamping lever 300 to bias clamping lever 300 towards the unclamped position.

Turning now to FIGS. 1-3, in conjunction with FIGS. 4A-14B, the assembly and operation of stapler 10 is described. Initially, firing assembly 500, followed by SULU 400, are loaded into cartridge receiving half-section 200. In order to load firing assembly 500 into proximal portion 208 of channel member 202 of cartridge receiving half-section 200, stationary housing 502 of firing assembly 500 is inserted into channel member 202 such that protrusion 504 (FIG. 10), which extends downwardly from stationary housing 502 of firing assembly 500 (see FIG. 10), is positioned within aperture 224 defined within base surface 220 of channel member 202. Once firing assembly 500 is loaded into channel member 202, SULU 400 can be loaded into distal portion 206 of channel member 202 via the engagement of distal protrusions 414 within cutouts 230. However, as noted above, at this point, the proximal end of SULU 400 will only partially seat within channel member 202 of cartridge receiving half-section 200 due to the bias of biasing member 526 (FIGS. 11A-11B), which urges the proximal end of SULU 400 from channel member 202.

Once SULU 400 and firing assembly 500 are loaded into channel member 202, anvil half-section 100 can be assembled to cartridge receiving half-section 200 by inserting bar 136 into vertical slots 228 of vertical support members 226 of cartridge receiving half-section 200 (see FIGS. 6A-6B). Thereafter, anvil half-section 100 may be rotated downwardly towards cartridge receiving half-section 200 to position lateral supports members 126 (FIGS. 4A-4B) in substantially U-shaped recesses 212 (FIG. 7B).

With anvil half-section 100 and cartridge receiving half-section 200 pivotably engaged to one another, clamping lever 300 may be engaged to cartridge receiving half-section 200. Referring to FIGS. 2-3 and 14A-14B, to engage clamping lever 300 to cartridge receiving half-section 200, flange portions 308 of clamping lever 300 are approximated about central portion 210 of cartridge receiving half-section 200 such that cylindrical pivot members 216 (FIG. 3) of cartridge receiving half-section 200 are inserted into substantially C-shaped recesses 314 of clamping lever 300. Thereafter, clamping lever 300 may be rotated in a counter-clockwise direction (according to the orientation shown in FIG. 2) about pivot member 216 (FIG. 3) and relative to cartridge receiving half-section 200 to the intermediate position. In the intermediate position, projections 312 (FIG. 14B) are received within apertures or dimples 218 (FIG. 3) to retain clamping lever 300 in the intermediate position relative to cartridge receiving half-section 200.

In use, in order grasp tissue between anvil half-section 100 and SULU 400, surgical stapler 10 is positioned such that tissue to be grasped is disposed between anvil half-section 100 and SULU 400. Thereafter, clamping lever 300 is rotated in the counter-clockwise direction from the intermediate position to the clamped position shown in FIG. 1 to approximate staple deforming portion 106 of anvil half-section 100 and top surface of SULU 400 to grasp tissue therebetween. As clamping lever 300 is rotated towards the clamped position, lateral support members 126 are received in cutouts 310 (FIG. 2) of flange portions 308 of clamping lever 300 and support fingers 125 engage SULU 400 to urge SULU 400 downwardly to be fully seated within channel member 202 of cartridge receiving half-section 200 against the bias of biasing member 526 (FIGS. 11A-11B). When SULU 400 is fully seated in channel member 202, SULU 400 is moved into operative engagement with firing assembly 500 such that knife actuating bar 508 and knife 406 are operably engaged to one another to permit actuation of firing assembly 500.

With surgical stapler 10 in the clamped, unfired position, firing lever 516 is pivoted to either side of stapler 10 to facilitate actuation of surgical stapler 10 from either side of the stapler 10. With firing lever 516 pivoted to the desired side of stapler 10, the corresponding lever guide projection 522 of the finger engagement member 518, 520 of firing lever 516 is positioned within the corresponding mouth 318 of a guide slot 316 of clamping lever 300 (FIG. 1). In this position, stapler 10 may still be unclamped, but is ready for firing.

In order to fire stapler 10, the finger engagement member 518, 520 of firing lever 516 is advanced distally along channel member 202, in the direction indicated by arrow “A” in FIG. 1. Upon initial distal advancement of the finger engagement member 518, 520, the lever guide projection 522 is moved from mouth 318 of a respective slot 316 of clamping lever 300 into the lever guide slot 316 to inhibit unclamping of clamping lever 300 during the firing stroke and to guide translation of firing lever 516 through the firing stroke. As firing lever 516 is advanced distally, slide block 514 is moved distally within stationary housing 502 of firing assembly 500 to effect corresponding movement of cam bar 510 and delayed movement of knife actuating bar 508. As cam bar 510 is moved distally through stationary housing 502 of firing assembly 500 and into SULU 400, the cam surfaces of cam bar 510 sequentially engage the pushers (not explicitly shown) disposed within SULU 400 to eject the staples (not explicitly shown) from body 402, through tissue, and into staple deforming portion 106 of anvil half-section 100 for forming the staples about tissue. Concurrently, since the distal end of knife actuating bar 508 is engaged with knife 406, knife 406, after the preset delay, is advanced through SULU 400 to incise tissue between the lateral rows 115 (FIG. 12B) of staples (not shown).

When firing lever 516 is returned to its proximal-most position to retract cam bar 510 and knife 406 after completion of the firing stroke, lever guide projection 522 is moved from lever guide slot 316 back to mouth 318 of the respective slot 316, thus permitting clamping lever 300 to move back to the intermediate position. Thereafter, clamping lever 300 may be disengaged and removed from cartridge receiving half-section 200 and stapler 10 may be moved to the open position to release the stapled and divided tissue. In the open position, anvil half-section 100 is spaced from cartridge receiving half-section 200 such that biasing member 526 (FIGS. 11A-11B) urges the proximal end of SULU 400 from a fully-seated position within channel member 202, thereby facilitating the removal of SULU 400 from channel member 202.

During a surgical procedure, SULU 400 can be replaced multiple times to facilitate multiple uses of stapler 10 on a single patient. For example, during a surgical procedure to remove a diseased portion of a vessel from the vessel, the surgical stapler 10 can be used to staple and cut tissue on opposite sides of the diseased vessel portion. The SULU 400 can be replaced after each staple and cut operation of the surgical stapler 10. Since each SULU 400 is provided with a fresh knife 406, tearing of tissue is minimized. After the surgical procedure, the used SULU(S) 400 and firing assembly 500 can be removed from channel member 202 and disposed of in an appropriate manner. The anvil half-section 100, cartridge receiving half-section 200 and clamping lever 300, as mentioned above, can then be sterilized, such as by autoclaving, and reused with a new SULU 400 and firing assembly 500 in the manner discussed above.

It will be understood that various modifications may be made to the embodiments of the surgical fastener applying apparatus disclosed herein. Therefore, the above description should not be construed as limiting, but merely as exemplifications of embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the present disclosure. 

What is claimed is:
 1. A surgical fastener applying apparatus comprising: an anvil half-section including a distal anvil portion and a proximal handle portion; a cartridge receiving half-section defining an elongated channel member, the elongated channel member having a distal portion dimensioned to releasably receive a single use loading unit and a proximal portion configured to support a firing assembly, the firing assembly including a stationary housing and a firing lever having at least one lever guide projection extending from the firing lever, the firing lever being slidable from a proximal end of the stationary housing to a distal end of the stationary housing to define a firing stroke; a clamping lever secured to the cartridge receiving half-section and including a proximal handle portion, the clamping lever being operably associated with the anvil half-section and the cartridge receiving half-section and being movable from an unclamped position to a clamped position to releasably secure the distal anvil portion of the anvil half-section in close approximation with the single use loading unit, the proximal handle portion of the clamping lever defining at least one lever guide slot, wherein the at least one lever guide projection is positioned to enter the at least one lever guide slot upon initiation of the firing stroke to inhibit movement of the clamping lever to the unclamped position during the firing stroke; and a biasing member supported in a distal end of the firing assembly, the biasing member being configured to inhibit full seating of the single use loading unit within the elongated channel member prior to movement of the clamping lever to the clamped position.
 2. The surgical fastener applying apparatus according to claim 1, wherein the clamping lever is releasably secured to the cartridge receiving half-section.
 3. The surgical fastener applying apparatus according to claim 1, wherein at least one of the proximal handle portion of the anvil half-section and the proximal handle portion of the clamping lever defines a plurality of apertures to facilitate cleaning and sterilization of the anvil half-section and/or the clamping lever.
 4. The surgical fastener applying apparatus according to claim 1, wherein the distal anvil portion of the anvil half-section defines a longitudinal slot extending therethrough, the longitudinal slot defining a relatively narrow bottom portion and a top portion that increasingly widens in a direction extending away from the bottom portion.
 5. The surgical fastener applying apparatus according to claim 1, wherein the firing assembly includes a stationary housing having a bottom surface and a protrusion extending downwardly from the bottom surface wherein the proximal portion of the elongated channel member of the cartridge receiving half-section defines an aperture configured to receive the protrusion of the stationary housing to releasably secure and align the firing assembly within the elongated channel member.
 6. The surgical fastener applying apparatus according to claim 1, wherein the firing assembly is configured to be releasably secured within the cartridge receiving half-section prior to releasably securing the single use loading unit within the elongated channel member.
 7. The surgical fastener applying apparatus according to claim 1, wherein the anvil half-section includes a proximally located bar and the cartridge receiving half-section includes a pair of proximally located support members that each define a vertical slot, the bar being configured to be received within the vertical slots to pivotably support the anvil half-section in relation the cartridge receiving half-section.
 8. The surgical fastener applying apparatus according to claim 1, wherein the clamping lever includes a pair of inwardly-extending projections and wherein the cartridge receiving half-section defines a pair of dimples, the projections of the clamping lever being configured to be received within the dimples of the cartridge receiving half-section to releasably retain the clamping lever in an intermediate position between the clamped position and the unclamped position.
 9. The surgical fastener applying apparatus according to claim 1, wherein the at least one lever guide slot has a mouth and wherein the at least one lever guide projection is positioned to enter the mouth of the at least one lever guide slot upon movement of the clamping lever to the clamped position.
 10. A surgical fastener applying apparatus comprising: an anvil half-section including a distal anvil portion and a proximal handle portion; a cartridge receiving half-section defining an elongated channel member, the elongated channel member having a distal portion dimensioned to releasably receive a single use loading unit and a proximal portion configured to support a firing assembly, the firing assembly including a firing lever, the firing lever slidable to define a firing stroke; a clamping lever secured to the cartridge receiving half-section and including a proximal handle portion, the clamping lever being operably associated with the anvil half-section and the cartridge receiving half-section and being movable from an unclamped position to a clamped position to releasably secure the distal anvil portion of the anvil half-section in close approximation with the single use loading unit; and a biasing member positioned in relation to the cartridge receiving half-section to inhibit full seating of the single use loading unit within the elongated channel member prior to movement of the clamping lever to the clamped position.
 11. The surgical fastener applying apparatus according to claim 10, wherein the firing lever has at least one lever guide projection and the proximal handle portion of the clamping lever defines at least one lever guide slot, the at least one lever guide projection being positioned to enter the at least one lever guide slot upon initiation of the firing stroke to inhibit movement of the clamping lever to the unclamped position during the firing stroke.
 12. The surgical fastener applying apparatus according to claim 11, wherein the firing assembly includes a stationary housing.
 13. The surgical fastener applying apparatus according to claim 11, wherein the at least one lever guide slot has a mouth and wherein the at least one lever guide projection is positioned to enter the mouth of the at least one lever guide slot upon movement of the clamping lever to the clamped position.
 14. The surgical fastener applying apparatus according to claim 10, wherein the clamping lever is releasably secured to the cartridge receiving half-section.
 15. The surgical fastener applying apparatus according to claim 10, wherein at least one of the proximal handle portion of the anvil half-section or the proximal handle portion of the clamping lever defines a plurality of apertures to facilitate cleaning and sterilization of the anvil half-section and/or the clamping lever.
 16. The surgical fastener applying apparatus according to claim 10, wherein the distal anvil portion of the anvil half-section defines a longitudinal slot extending therethrough, the longitudinal slot defining a relatively narrow bottom portion and a top portion that increasingly widens in a direction extending away from the bottom portion.
 17. The surgical fastener applying apparatus according to claim 10, wherein the firing assembly includes a stationary housing having a bottom surface and a protrusion extending downwardly from the bottom surface, wherein the proximal portion of the elongated channel member of the cartridge receiving half-section defines an aperture configured to receive the protrusion of the stationary housing to releasably secure and align the firing assembly within the elongated channel member.
 18. The surgical fastener applying apparatus according to claim 10, wherein the firing assembly is configured to be releasably secured within the cartridge receiving half-section prior to releasably securing the single use loading unit within the elongated channel member.
 19. The surgical fastener applying member according to claim 10, wherein the biasing member is supported on a distal end of the firing assembly.
 20. The surgical fastener applying apparatus according to claim 10, wherein the anvil half-section includes a proximally located bar and the cartridge receiving half-section includes a pair of proximally located support members each defining a vertical slot, the bar being configured to be received within the vertical slots to pivotably support the anvil half-section in relation to the cartridge receiving half-section.
 21. The surgical fastener applying apparatus according to claim 10, wherein the clamping lever includes a pair of inwardly-extending projections and wherein the cartridge receiving half-section defines a pair of dimples, the projections of the clamping lever being configured to be received within the dimples of the cartridge receiving half-section to releasably retain the clamping lever in an intermediate position between the clamped position and the unclamped position. 